How to Switch Nagios XI to the Faster Compiled check_ncpa Plugin

As of Nagios XI 2026R1.7, there is an option to use either the legacy Python version of check_ncpa.py or a new compiled version of check_ncpa, the plugin Nagios XI uses to run checks against the Nagios Cross-Platform Agent (NCPA). The new binary version has been shown to execute much faster, should be a command-line match with the Python version, and should work as a drop-in replacement.

Performance Comparison

Below are screenshots of the top output of a lab machine configured with approximately 13,000 checks running check_ncpa.py:

And the same machine running the compiled version of check_ncpa:

Before You Begin

The new binary version is being configured by default on new installations of XI 2026R1.7. Upgraded systems keep the Python version by default so that customers can decide to opt in if they have not made any customizations to the Python version of the plugin.

If you want to test the new version of check_ncpa on your upgraded system or switch back to using the Python version, please use the steps below.

As always, we recommend testing the script in your test environment prior to using it in production.

Please note that if you are running Nagios Mod-Gearman (NMG) checks, we recommend waiting for a future version as the current version does not work properly with NMG.

Switching to the Compiled check_ncpa Plugin

1. Before making changes, back up your current configuration. Navigate to Core Configuration Manager (CCM) > Quick Tools > Configuration Snapshots and confirm a recent snapshot is listed. If the switch causes problems, you can restore this snapshot to return to your previous configuration.
2. Navigate to Configure > Core Config Manager > Commands > Commands in the Nagios XI web interface.
3. Search for check_xi_ncpa and click the Edit icon.

4. Change the Command Line from $USER1$/check_ncpa.py to $USER1$/check_ncpa, leaving the remainder of the command intact.

This will force the checks to use the new version of check_ncpa.

5. Click Save, then click Apply Configuration.

Switching Back to the Python Version

To switch back to the Python version, repeat steps 2-5 and change $USER1$/check_ncpa back to $USER1$/check_ncpa.py.

Conclusion

The compiled check_ncpa plugin lets your Nagios XI server run the same NCPA checks with significantly less overhead, freeing capacity to monitor more of your environment on existing hardware. Because the change applies to every service using the check_xi_ncpa command, validate it in a test environment and take a configuration snapshot before switching production systems. If you need to return to the original plugin, switching back takes only a single command edit.

Looking for more ways to get the most out of Nagios XI? Browse the Nagios Library for documentation and how-to guides, or visit Nagios Support if you have questions about switching to the compiled plugin.